The UN has slapped a global port ban on four vessels found violating sanctions against North Korea, the head of an expert panel said on Monday in what he described as an unprecedented move.

The United States led a drive at the Security Council to impose two recent sets of sanctions to punish Pyongyang over its nuclear and missile tests.

"There are four vessels that have been designated by the committee. The designation doesn't mean an assets freeze or travel ban. But it's a port ban," said Hugh Griffiths, coordinator of a UN Security Council panel on North Korea sanctions, adding the ships were found "transporting prohibited goods."

"It's a pretty swift and decisive action by the committee," he said, adding that the ban went into effect on October 5.

Griffiths was speaking at the conclusion of the second UN meeting on enforcing North Korea sanctions.

A source close to the matter said the four ships were found carrying coal, seafood and iron ore, exports banned by a UN resolution imposed in August.

The ban was expanded last month to include textiles and North Korean guest workers and also capped oil exports.

North Korean diplomats were present at the meeting but did not speak, according to diplomats.

According to a source, the listed ships were the Petrel 8, Hao Fan 6, Tong San 2 and Jie Shun. According to the MarineTraffic website, the first three fly the flags of Comoros, Saint Kitts and Nevis, and North Korea. The Jie Shun is not listed on the site.